Multi-ply paperboard prepared from recycled materials and methods of manufacturing same
AssigneeRock-Tenn Company
InventorsJames K. Hansen, Richard L. Munson, Jr., Roberto Balaguer, Jr., Jeffrey M. Leitinger, Thomas F. Barton
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Abstract
This invention, in one aspect, relates to a multi-ply paperboard having at least three inner plies and, in some aspects, a top liner and a back liner, wherein the multi-ply paperboard is derived from fiber sources comprising at least about 80% by weight recycled fiber. The multi-ply paperboard of the present invention exhibits strength characteristics comparable those of paperboard prepared from virgin board. In further aspects, the invention relates to methods of making the multi-ply paperboard of the present invention.
Claims33
A multi-ply paperboard having at least three inner plies wherein the inner plies together form a filler section having a first filler section side and a second filler section side, wherein the inner plies are derived from one or more inner ply fiber sources comprising at least about 80% by weight recycled fiber, wherein the MD/CD stiffness ratio of the multi-ply paperboard is from about 1.3 to about 2.3, wherein the values providing the ratio are measured according to TAPPI method 489-om-92, wherein the multi-ply paperboard is scorable, and wherein the paperboard has a thickness of from about 0.010 to about 0.050 in.
A multi-ply paperboard having at least three inner plies, wherein the inner plies together form a filter section having a first filler section side and a second filler section side, wherein the inner plies are derived from one or more inner ply fiber sources comprising at least about 80% by weight recycled fiber, wherein the paperboard has a MD stiffness value of from about 100 to about 1100 and a CD stiffness value of from about 50 to about 550 as measured by TAPPI method 489-om-92, and wherein the multi-ply paperboard is scorable.
A multi-ply paperboard having at least three inner plies, wherein the inner plies together form a filler section having a first filler section side and a second filler section side, wherein the inner plies are derived from one or more inner ply fiber sources comprising at least about 80% by weight recycled fiber, wherein the paperboard has a MD dry tear strength of from about 300 to about 900 and a CD dry tear strength of from about 300 to about 900 as measured by TAPPI method 414-om-88, and wherein the multi-ply paperboard is scorable.
A method for making a multi-ply paperboard having at least three inner plies comprising the steps of:
- a. introducing an inner ply pulp stock into at least one fourdrinier-type machine having a pulp stock instruction point, a forming fabric and an induction means wherein:
- i the pulp stock comprises water and an inner ply fiber derived from an inner ply fiber comprising at least about 80% by weight recycled fiber;
- b. directing the forming fabric away from the pulp stock introduction point;
- c. draining water from the pulp stock thereby providing at least one inner ply;
- and
- d. collecting the at least one inner ply with at least two additional inner plies to provide a filler section, wherein the filler section is suitable for use in a multi-ply paperboard having at least three inner plies,
- wherein the pulp stock has a velocity A, the forming fabric has a velocity B and velocity A is greater than velocity B, wherein the multi-ply paperboard has a MD/CD stiffness ratio of from about 1.3 to about 2.3, wherein the MD and CD values providing the ratio are each measured by TAPPI method 489-om-92, and wherein the multi-ply paperboard is scorable.
Dependencies are inferred from the claim text.